Characterization of Poly-Amorphous Indomethacin by Terahertz Spectroscopy

Since the stability of amorphous solids of pharmaceuticals differs depending on the method of preparation, there are several solid-state chemical structures in amorphous solids, which like poly-amorphous solids might have different characteristics the same as in crystalline solids. However, it is not easy to identify the differences in solid-state characteristics between amorphous solids using conventional analytical methods, such as powder X-ray diffraction analysis, since all of the poly-amorphous solids had similar halo X-ray diffraction patterns. However, terahertz spectroscopy can distinguish the amorphous solids of indomethacin with different physicochemical properties, and is expected to provide a rapid and non-destructive qualitative analysis for the solid materials, it would be useful for the qualitative evaluation of amorphous solids in the pharmaceutical industry.     

Effect of glycine on 5-aminolevulinic acid biosynthesis in heterotrophic culture of Chlorella regularis YA-603

Chlorella regularis strain YA-603 was previously found to exhibit a comparatively high growth rate and improved 5-aminolevulinic acid (ALA) productivity when cultured heterotrophically. Although the universal tetrapyrrole precursor ALA is synthesized from glutamate in algae and higher plants, in this study the addition of glutamate to the medium did not enhance ALA production in the heterotrophic culture of C. regularis YA-603. On the other hand, the addition of glycine, which is a precursor of ALA biosynthesis via the Shemin pathway in animal cells and some bacteria, enhanced both the specific growth rate and ALA production. Moreover, when a second glycine addition was made during the culture, the ALA concentration increased by about 1.5 times compared to that obtained with one glycine addition. From these results, it is suggested that the Shemin pathway contributes to ALA production, and that addition of glycine in the heterotrophic culture of C. regularis YA-603 can significantly increase the amount of ALA produced.     

Improvements in the hygroscopic properties of cotton cellulose by treatment with an endo-type cellulase from Streptomyces sp. KSM-26

The effect of enzymatic cellulolysis on the moisture-adsorbing properties of cotton cellulose was investigated, using a highly purified endo-type cellulase from Streptomyces sp. KSM-26. The time course of changes in the hygroscopicity of cotton reflected the time course of changes in the extent of the amorphous state of cotton, which was estimated from the amount of water that could bind to cotton, as determined by differential scanning calorimetry, during the hydrolytic process. The endo-type cellulase increased the degree of freedom of cellulose chains in the amorphous regions of cotton at the initial stage of the hydrolytic reaction, leading to major improvements in the moisture-adsorbing properties of cotton. The cellulase then caused the rapid decrease in the size of the amorphous regions with the release of reducing sugars as endo-cleavages in the amorphous regions increased, which reduced the hygroscopicity. The decrease in the hygroscopicity of cotton during enzymatic hydrolysis was followed by a second increase, as the cotton became more amorphous as a consequence of further hydrolysis of the crystalline regions of cotton. The effect of cellulase on the apparent degree of polymerization and the physical strength of cotton became detectable at the later stage of cellulolysis.